class Student{
    allName:string;
    constructor (public firstName,public middName,public lastName){
        this.allName=firstName+""+middName+""+lastName;
    }
}
interface Person{
    firstName:string,
    middName:string,
    lastName:string
}

function getName(personName:Person){
    console.log(personName)
}
var user=new Student("张三","李四","王五");

getName(user);